Apparatus and process for preparing quantitative chemical solutions

• US 4,469,146 A
• Filed: 02/10/1982
• Issued: 09/04/1984
• Est. Priority Date: 02/10/1982
• Status: Expired due to Term

• Current Assignee: Spiral Biotech, Inc. (Advanced Instruments Inc.)
• Original Assignee: Spiral Systems, Inc.
• Inventors: Campbell, Jeptha E., Gilchrist, James E.
• Primary Examiner(s): Marcus, Stephen
• Assistant Examiner(s): Thronson, Mark
• Application Number:
  US06/347,467
• Time in Patent Office: 937 Days
• Field of Search: 141/1, 141/9, 141/83, 141/100, 177/25, 177/70, 364/502, 422/67
• US Class Current: 141/9
• CPC Class Codes: G01G 15/02 with provision for adding or removing a make-up quantity of material to obtain the desired net weight dribble-feed means for automatic batch-weighers G01G13/04
• CPC Class Codes: G01G 19/343 involving digital counting
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2035/00217 involving measurement of weight

Abstract

This invention is an apparatus for making solutions of chemicals of specified molarity, normality, molality or weight percentage corrected, as necessary, for water of hydration in the solute. By means of an input-output device using a programmed instruction format, the desired chemical, the type of solution wanted, its concentration, and its volume are specified. An electronic balance with TARE capability repeatedly produces an output signal of the weight W of solute plus any solvent within a container in which the solution is to be mixed less the weight of the container. Apparatus are provided for calculating and storing the weight TW which is the total weight of the solute plus solvent which will result in a solution of the type and concentration of solution specified for the amount of solute placed on the balance. If the total volume of solution of the desired type and concentration of solution is specified, apparatus are provided for determining the amount of solute required. Means are provided for controlling the flow of solvent between a source and the container for causing the flow of solvent into the container when TW-W is greater than zero and to stop the flow of solvent into the container when TW-W=0. Apparatus are provided to prevent overfilling the container.

Claims

1. An apparatus for making a solution of specified molarity from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within the container;

(b) means for specifying the molarity M of the solution to be mixed from a solute within the container by the addition of solvent to the container;

(c) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solution of the specified molarity M within the container;

(d) means for calculating TW wherein ##EQU15## WS equals the weight of the solute which is added to the container that is necessary to make the solution of specified molarity prior to mixing, K equals the specific gravity of a one molar solution of the solute measured at a particular temperature -1, and FW equals the gram molecular weight of the solute;

(e) means for calculating TW-W; and

(f) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

2. The apparatus of claim 1 wherein the quantity [1+(K×

M)] is multiplied by a scaling factor SG wherein SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of the solute at any temperature at which the solution is mixed from the specific gravity of a one molar solution of the solute used in calculating K which is based upon measurement of specific gravity at a particular temperature.

3. An apparatus for making a solution of specified normality from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the normality N of the solution to be mixed from a solute within the container by the addition of solvent to the container;

(c) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for the purpose of mixing the solution of the specified normality within the container;

(d) means for calculating TW wherein ##EQU16## k equals the specific gravity of a one molar solution of the solute at a particular temperature -1, WS equals the weight of the solute which is added to the container that is necessary to make the solution of specified normality, N equals the normality and v equals the valence of the solute;

(e) means for calculating TW-W; and

(f) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

4. The apparatus of claim 3 wherein the quantity 1+K/V×

N is multiplied by a scaling factor SG wherein SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of solute at any temperature at which the solution is mixed from the specific gravity of the solute used in calculating K which is based upon measurement of specific gravity at a particular temperature.

5. An apparatus for making a solution of specified molarity and approximate volume from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the molarity M of the solution to be mixed within a container by the addition of solvent to the container;

(c) means for specifying approximate volume V of the solution to be mixed;

(d) means for calculating a gravimetric equivalent TW of the solution of volume V to be mixed wherein TW is calculated from the equation

space="preserve" listing-type="equation">TW=(V)[1+(K×

M)]

and is equal to the combined weight of solvent plus solute necessary to make the specified volume V of molar solution, and K equals the specific gravity of a one molar solution of the solute at a specified temperature -1 and M is the desired molarity;

(e) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solution;

(f) means for calculating WS from the equation ##EQU17## wherein WS equals the weight of the solute which is necessary to make the solution of specified molarity M and volume V, and FW equals the gram molecular weight of the solute;

(g) means for alerting an operator when the weight of solute which has been placed within the container is equal to or greater than the calculated weight WS;

(h) means for calculating TW in accordance with the equation ##EQU18## wherein WS is the weight of solute which has been added to the container that is less than, equals or exceeds the calculated WS;

(i) means for calculating TW-W; and

(j) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

21. An apparatus for making a solution of specified molarity and approximate volume in accordance with claim 5 wherein the quantity 1+K×

M is multiplied by a scaling factor SG wherein SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of solute at any temperature at which the solution is mixed from the specific gravity of the solute used in calculating K which is based upon a measurement of specific gravity at a particular temperature.

6. An apparatus for making a solution of specified normality and approximate volume from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the normality N of the solution to be mixed within a container by the addition of solvent to the container which has the solute in it;

(c) means for specifying an approximate volume V of the solution to be mixed;

(d) means for calculating a gravimetric equivalent TW of the solution of volume V to be mixed wherein TW is calculated from the equation ##EQU19## and is equal to the combined weight of solvent plus solute necessary to make the specified volume of normal solution wherein K equals the specific gravity of a one molar solution of the solute at a specified temperature -1, and v is the valence of the solute;

(e) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solution;

(f) means for calculating WS from the equation ##EQU20## wherein WS equals the weight of the solute which is necessary to make the solution of specified normality N and volume V, and FW equals the gram molecular weight of the solute;

(g) means for alerting an operator when the weight of the solute which has been placed within the container is equal to or greater than the calculated weight WS;

(h) means for calculating TW in accordance with the equation ##EQU21## wherein WS is the weight of solute which has been added to the container that is less than, equals or exceeds the calculated WS;

(i) means for calculating TW-W; and

(j) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

22. An apparatus for making a solution of specified normality and approximate volume in accordance with claim 6 wherein the quantity 1+K/v×

N is multiplied by a scaling factor SG wherein SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of solute at any temperature at which the solution is mixed from the specific gravity of the solute used in calculating K which is based upon a measurement of specific gravity at a particular temperature.

7. An apparatus for making a solution of specified molality and approximate volume from a solute placed in a container by the addition of solvent into the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent with a container;

(b) means for specifying the molality m of the solution to be mixed within a container by the addition of solvent to the container;

(c) means for specifying an approximate volume V of the solution to be mixed;

(d) means for calculating a gravimetric equivalent TW of the solution of volume V to be mixed wherein TW is calculated from the equation

space="preserve" listing-type="equation">TW=(V)[1+K×

m]

and is equal to the combined weight of solvent plus solute necessary to make the specified volume V of molal solution, and K is the specific gravity of a one molar solution of the solute at a specified temperature -1;

(e) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solution;

(f) means for calculating WS from the equation ##EQU22## wherein WS equals the weight of the solute which is necessary to make the solution of specified molality m and volume V, FW equals the gram molecular weight of the solute and n equlas the number of water molecules associated with each molecule of solute within the crystalline structure of the solute;

(g) means for alerting an operator when the weight of the solute which has been placed within the container is equal to or greater than the calculated weight WS;

(h) means for calculating TW in accordance with the equation ##EQU23## wherein WS is a weight of solute which has been added to the container which is less than, equals or exceeds the calculated WS;

(i) means for calculating TW-W; and

(j) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

8. An apparatus for making a solution of specified weight percentage corrected for water of hydration and approximate volume from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the % of the solution to be mixed within a container by the addition of solvent to the container which has the solute in it;

(c) means for specifying an approximate volume V of the solution to be mixed;

(d) means for calculating a gravimetric equivalent TW of the solution to be mixed wherein TW is calculated from the equation ##EQU24## and is equal to the combined weight of solvent plus solute necessary to make the specified volume of % solution, n is the number of molecules of water combined in each molecule of solute, FW is the gram molecular weight of the solute and K equals the specific gravity of a one molar solution of the solute at specified temperature -1;

(e) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solution;

(f) means for calculating WS from the equation ##EQU25## wherein WS equals the weight of the solute which is necessary to make the solution of specified % corrected for water of hydration and volume V;

(g) means for alerting an operator when the weight of the solute which has been placed within the container is equal to or greater than the calculated weight WS;

(h) means for calculating TW in accordance with the equation ##EQU26## wherein WS is a weight of solute which has been added to the container which is less than, equals or exceeds the calculated WS;

(i) means for calculating TW-W; and

(j) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

9. A process for mixing solutions of specified molarity and approximate volume comprising:

(a) specifying a molarity M of a solution to be mixed in a container by the addition of a solvent to a solute within the container;

(b) specifying an approximate volume V of solution of the specified molarity M;

(c) calculating a weight of solvent plus solute TW for mixing the solution of specified approximate volume V;

(d) calculating a weight of solute WS required for mixing the solution with the weight TW of solute plus solvent;

(e) adding a weight of solute to the container which is less than, equal to or greater than WS;

(f) calculating a weight of solvent plus solute TW for mixing the solution of specified molarity M from the actual weight of solute WS which has been added to the container; and

(g) adding solvent to the container until the weight of solvent plus solute is equal to the calculated weight TW for mixing the solution of specified molarity M from the actual weight of solute WS which has been added to the container.

10. A process in accordance with claim 9 wherein:

(a) the calculation in step (c) of claim 9 is made in accordance with the equation

space="preserve" listing-type="equation">TW=(V)[1+(K×

M)]

wherein K equals the specific gravity of a one molar solution of the solute measured at a particular temperature -1;

(b) the calculation in step (d) of claim 9 is made in accordance with the equation ##EQU27## wherein FW equals the gram molecular weight of the solute; and

(c) the calculation in step (f) of claim 9 is made in accordance with the equation ##EQU28##

11. A process in accordance with claim 10 wherein the quantity 1+K×

M is multiplied by a scaling factor SG wherein SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of solute at any temperature at which the solution is mixed from the specific gravity of the solute used in calculating K which is based upon a measurement of specific gravity at a particular temperature.

12. A process for mixing solutions of specified normality and approximate volume comprising:

(a) specifying a normality N of a solution to be mixed in a container by the addition of a solvent to a solute within the container;

(b) specifying an approximate volume V of solution of the specified normality N;

(c) calculating a weight of solvent plus solute TW for mixing the solution of specified approximate volume;

(d) calculating a weight of solute WS required for mixing the solution with the weight TW of solute plus solvent;

(e) adding solute to the container which is less than, equal to or greater than WS;

(f) calculating a weight of solvent plus solute TW for mixing the solution of specified normality N from the actual weight of solute WS which has been added to the container; and

(g) adding solvent to the container until the weight of solvent plus solute is equal to the calculated weight TW necessary to mix the solution of specified normality N from the actual weight of solute WS which has been added to the container.

13. A process in accordance with claim 12 wherein:

(a) the calculation in step (c) of claim 12 is made in accordance with the equation ##EQU29## where K equals the specific gravity of a one molar solution of the solute at a particular temperature -1, and v equals the valence of the solute which is stored in memory;

(b) the calculation in step (d) of claim 12 is made in accordance with the equation ##EQU30## wherein FW equals the gram molecular weight of the solute and (c) the calculation in step (f) of claim 12 is made in accordance with the equation ##EQU31##

14. A process in accordance with claim 13 wherein the quantity 1+K/v×

N is multiplied by a scaling factor SG where SG is a scaling factor which corrects for the variation in specific gravity of a one molar solution of solute at any temperature at which the solution is mixed from the specific gravity of the solute used in calculating K which is based upon a measurement of specific gravity at a particular temperature.

15. A process for mixing solutions of specified molality and approximate volume comprising:

(a) specifying a molality m of a solution to be mixed in a container by the addition of a solvent to a solute within the container;

(b) specifying an approximate volume V of solution of the specified molality m;

(c) calculating a weight of solvent plus solute TW for mixing the solution of specified approximate volume;

(d) calculating a weight of solute WS required for mixing the solution with the weight TW of solute plus solvent;

(e) adding solute to the container which is less than, equal to or greater than WS;

(f) calculating a weight of solvent plus solute TW for mixing the solution of specified molality m from the actual weight of solute WS which has been added to the container; and

(g) adding solvent to the container until the combined weight of solvent plus solute is equal to the calculated weight TW necessary to mix the solution of specified molality m from the actual weight of solute WS which has been added to the container.

16. A process in accordance with claim 15 wherein:

(a) the calculation in step (c) of claim 15 is made in accordance with the equation

space="preserve" listing-type="equation">TW=(V)[1+(K×

m)]

wherein K equals the specific gravity of a one molar solution of the solute measured at a particular temperature -1;

(b) the calculation in step (d) of claim 15 is made in accordance with the equation ##EQU32## wherein FW equals the gram molecular weight of the solute and n is the valence of the solute; and

(c) the calculation in step (f) of claim 15 is made in accordance with the equation ##EQU33##

17. A process for mixing solutions of specified weight percentage corrected for water of hydration and approximate volume comprising:

(a) specifying a weight % of a solution to be mixed in a container by the addition of a solvent to a solute within the container;

(b) specifying an approximate volume V of solution of the specified weight %;

(c) calculating a weight of solvent plus solute TW for mixing the solution of specified approximate volume;

(d) calculating a weight of solute WS required for mixing the solution with a weight TW of solute M plus solvent;

(e) adding solute to the container which is less than, equal to or greater than WS;

(f) calculating a weight of solvent plus solute TW for mixing the solution of specified weight % from the actual weight of solute WS which has been added to the container; and

(g) adding solvent to the container until the combined weight of solvent plus solute is equal to the calculated weight TW necessary to mix the solution of specified weight % from the actual weight of solute WS which has been added to the container.

18. A process in accordance with claim 17 wherein:

(a) the calculation in step (c) of claim 17 is made in accordance with the equation ##EQU34## wherein K equals the specific gravity of a one molar solution of the solute measured, FW equals the gram molecular weight at a particular temperature -1 of the solute, and n is the number of molecules of water combined in each molecule of the solute;

(b) the calculation in step (d) of claim 17 is made in accordance with the equation ##EQU35## and (c) the calculation in step (f) of claim 17 is made in accordance with the equation ##EQU36##

19. An apparatus for making a solution of specified molarity from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly measuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the molarity M of the solution to be mixed from a solute within the container by the addition of solvent to the container;

(c) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for mixing the solutions of the specified molarity M within the container;

(d) means for calculating TW wherein TW is the combined weight of solvent plus solute necessary to make the solution;

(e) means for calculating TW-W; and

(f) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.

20. An apparatus for making a solution of specified normality from a solute placed in a container by the addition of solvent to the container comprising:

(a) means for repeatedly mesuring the weight W of the solute plus any solvent within a container;

(b) means for specifying the normality N of the solution to be mixed from a solute within the container by the addition of solvent to the container;

(c) fluid conducting means disposed between a source of solvent and the container for transferring solvent from the source to the container for the purpose of mixing the solution of the specified normality within the container;

(d) means for calculating TW wherein TW is the combined weight of solvent plus solute necessary to make the solution;

(e) means for calculating TW-W; and

(f) means responsive to the means for calculating TW-W for controlling the flow of solvent between the source and the container, the means for controlling causing the flow of solvent into the container to occur when TW>

W and to stop when TW=W.